The use of tinted, or colored, contact lenses that incorporate iris patterns to alter the natural color of the iris is well known. Typically, the patterns used in the tinted lenses are derived from artistic renderings of human iris patterns. The disadvantage of this design method is that the patterns, and colors used in the patterns, are not created with sufficient consideration for the interaction of the spectral and optical characteristics of the patterns when the lenses are on-eye. These optical characteristics include, without limitation, reflections, metamerism, and color summations such as the cumulative appearance of placing a transparent or translucent color over another color. Thus, the on-eye appearance of the lens' iris pattern is unpredictable as to both the geometric appearance and the blending of the colors with the eye's natural iris colors. In order to obtain a desirable design, many iterations of a design may need to be tested on-eye. Therefore, a need exists for a method of designing tinted lenses that overcome this disadvantage.